Carbonizing-flask



(No Model.)

T. A. EDISON.

. OARBONIZING FLASK. No. 411,017. Patented Sept. 1'7, 1889.

ATTEST: INVENTDR:

UNITED STATES PATENT OFFICE.

THOMAS A. EDISON, OF MENLO PARK, NEW JERSEY.

CARBONIZING-FLASK.

SPECIFICATION forming part of Letters Patent No. 411,017, dated September 17, 1889. Application filed April 17, 1883. Serial No. 91,951. (No model.)

To 0. whom it may concern.-

Be it known that I, THOMAS A. EDISON, of Menlo Park, in the county of Middlesex and State of New Jersey, have invented a new and useful Improvement in Oarbonizing-Flasks, (Case N o. 554,) of which the following is a specification.

This invention relates to flasks for carbonizing, and especially to those used in the manufacture of the incandescing filaments of electric lamps, my object being to construct such flasks so as to prevent, as far as possible, the admission of air to the interior. Such flasks have hitherto usually consisted of a flat base, on which the molds containing the carbonizable filaments were piled one above another, and a cover placed upon said base and inclosing the molds, the junction between the base and the edge of the cover beingluted to form an air-tight joint. It has been found that this construction is sometimes not efficient in preventing the admission of air, and by my present invention I improve upon the old form by forming the base with a raised edge entirely around it and at a little distance from the cover. The space between the raised edge and the cover is filled with the luting material. Preferably carbonized cotton, which is an absorbent of oxygen, is placed beneath the edges of the cover, and the space surrounding the cover is filled with powdered graphite or plumbago. This, it is found, effectually prevents the admission of air within the cover.

The invention is illustrated in the accompanying drawing, which is a vertical section of a carbonizing-fiask embodying said invention.

Ais the base, and B the cover placed thereon and inclosing the molds C, piled one'above another and containing the material to be carbonized. The base A is provided with a raised edge D, extending entirely around its circumference. After the cover B is set upon the base with the carbonized cotton underits edges, the space between said cover and the raised edge D is packed with the powdered graphite E.

I have found that this construction is very efficient in preventing the entrance of oxygen to the filaments or other carbonizable bodies placed within the flask.

' All the parts of the flask should be made of plumbago, nickel, or other material capable of withstanding high temperatures.

What I claim is 1. A carbonizing-flask constructed of a ma.- terialsuch as plumbago or nickel-capable of withstanding a high temperature and composed of a base with a raised edge, a cover resting on said base within the raised edge and leaving a space between said cover and edge, a lutingsuch as graphitecapable of withstanding a high temperature placed in said space, and an absorbent of oxygen placed in the jointbetween the parts of the flask, substantially as set forth.

2. A carbonizing-flask constructed of a material-such as plumbago or nickel-capable of withstanding a high temperature and composed of a base with a raised edge, a cover resting on said base within the raised edge and leaving a space between said cover and edge, a luting-such as graphite-capable of withstanding a high temperature placed in said space, and a body of carbonized cotton placed in the joint between the parts-of the flask, substantially as set forth.

This specification signed and witnessed this 6th day of April, 1883.

, THOS. A. EDISON. Witnesses:

H. W. SEELY, EDWARD H. PYATT. 

